Pulse regenerator



Feb..l0, 1942. SWARTZEL, JR 2,272,590

PULSE REGENERATOR Filed June 21, 1940 //V|/EN TOR K 0. I SWAR TZEL,JR.

' A 7TORNEV Patented Feb. 10, 1942 PULSE REGENERATOR Karl D. Swartzel,J12, Teaneck, N. J., assignor to Bell Telephone Laboratories,Incorporated, New York, N. Y., a corporation of New York ApplicationJune 21, 1940, Serial No. 341,610

8 Claims.

This invention relates to signaling systems and particularly to impulseregenerating means used in telephone systems.

The object of the invention is to provide simple and economical meansresponsive to dialed subscriber line impulses for sending out similartrains of impulses regenerated by means which will assure the properstrength, length and timing thereof regardless of any mutilation of theincoming impulses.

A feature of the invention is the use of the so-called pocket and dippermethod for measuring both the number of incoming and outgoing pulses.According to this feature the incoming impulses are translated into acorresponding number of increments of energy which are placed one at atime in a receiver capable of holding them until they are again takenout one at a time and counted. Specifically, a comparatively largecapacity condenser is provided and this is successively charged by thetransfer of the charges from a comparatively small capacity condenser.The level to which this comparatively larg capacity is charged is ameasure of the number of impulses in the incoming train. When the trainhas thus been registered, another small capacity condenser is employedto discharge the storage condenser by successively taking therefromincrements of energy until the said storage condenser is practicallyempty. By properly adjusting the circuits and the capacity of two smallcondensers employed the number of increments of energy subtracted may beexactly equal to the number added and in this manner the incoming trainof impulses may be faithfully reproduced in number. Since the outgoingpulses under precision are machine controlled, their strength andduration may be rigidly controlled.

Another feature of the invention is a simple step-by-step switch forbringing a different large capacity condenser for each digit under theinfluence of said small condensers.

The drawing consists of a single sheet in which Fig. 1 is a circuitdiagram by which the invention will be explained.

A subscribers station I provided with a dial 2 may be connected to thepulse regenerator of the present invention by means of a switch hereillustrated by the contacts 3 and brushes 4. By means of this switch thelines are connected to a conventional line relay 5. Relays 5, B and Iare the conventional A, B and. C relays used in automatic telephoneworking. Relay 5 responds to the seizure of the line and releases uponeach interruption thereof representing a digit impulse.

winding of relay 2 brings a pawl into position so that upon the re- 1lease of magnet 8 ratchet 9 will be advanced one step and therefore thebrush I0 will be stepped forward from one contact to another. Brush I0sweeps over a plurality of contacts to each of which a condenser, suchas l I, is connected. This condenser is of a comparatively largecapacity.

Relay 5, through its upper armature, controls the connection from acomparatively small capacity condenser l2 which is alternately chargedby the battery I3 and then discharged through the wiper l0 intocondenser ll. Thus when the dial 2 is operated the small capacitycondenser 12 will be discharged an equal number of times into the largecapacity condenser H and at the end of this train of impulses the magnet8 will advance the brush ill to another contact.

The balance of the circuit is a precision means for sending out acorresponding number of impulses to set the switch represented by thecontacts M on to the terminals [5 leading to a subscribers station 16,by way of example. A power driven shaft I! is provided with a cam l8which operates a set of contacts periodically. By means of the machineoperated contact I!) a connection to the distant point will be closedperiodically and at uniformly spaced intervals. Let it be assumed thatthe motor magnet 20 has moved brush 2| into connection with a terminalleading to a condenser 22 which has been charged by a series of digitimpulses coming from the substation I. Relay 23 is a sensitive marginalor polarized relay which operates to close its contacts because of thecharged condenser 22 now connected to it. When its inner armature isoperated, a circuit is closed from the winding of relay 2A through thearmature and front contact of relay 23, through the contacts 26 whenthey are next closed, to battery and thence the Contacts 26 which closeonly when the outpulsing contacts l9 are closed serve to prevent thefirst pulse of a digit from being fractional in duration as would occurif contacts l9 were elfectively connected to the output sometime duringthe break. When relay 24 operates it provides a locking circuit foritself through its lower armature and front contact. At its outer upperarmature and back contact relay 24 opens a contact which normally shuntsthe pulsing contacts l9 and contacts H! are now rendered operative. Thetransfer contacts 21 now operate to periodically charge the condenser 28from a battery 29 and to discharge it through the circuit completed bythe inner upper armature and front contact of relay 24. It will be notedthat this battery is reversed in relation to battery l3 so that thecharges on the comparatively small capacity condenser 28 are in reverseddirection to those on the small capacity condenser l2; therefore, eachtime the contacts 21 move to the position shown and after relay 24 hasbeen operated, the charge on condenser 22 will be reduced by acorresponding amount. Since condensers l2 and 28 may be accuratelymatched, the number of charges taken from the condenser 22 may be madeexactly equal to the number put in. When the capacity of the condenser22 is therefore reduced to a critical value the relay 23 becomesreleased. This in turn releases relay 24 and shunts the pulsing contactsl9 so that the number of machine-made interruptions of the circuit whichleads to the switch represented by the brushes M will be limited. Therelease of relay 23 also releases relay 25 which after an interval timedby the slow releasing characteristics of rela 25 to the properinterdigit pause, releases stepper 20 so that brush 2| is advanced tothe next contact.

It should be noted that the means herein disclosed to respond to thecharge on condenser 22 is a relay 23. It is important that this behighly sensitive and also of such high impedance that the condenser 22will not be discharged too rapidly thereby. While this is shown as aconventional relay it is to be understood that it may be of any othertype, such as a relay responsive to a vacuum tube which in turn willaccurately respond to the raised potential of condenser 22 withoutdissipating its charge.

In order to prevent the precision outpulsing arrangement overtaking theimpulsing arrangement, two additional relays 30 and 3| are provided.Relay 30 is in parallel with relay 1 and therefore attracts its armaturewhen the first digit is dialed. It is made very slow to release and willtherefore hold over during the interdigit dialing period unless thesubscriber at station I is more than ordinarily slow. Relay 3| isarranged in a circuit including a normal contact of relay 35) and afront contact of relay 6, so that as soon as the apparatus is seized andrelay is energized relay 30 will become energized. Relay 3| causes relay25 to become energized and therefore operates stepping magnet 20. Aslong as relay 3| remains operated magnet cannot be released to step thebrush 2|. Relay 3| is very slow to releaseof the same order as relay 3E!though preferably slightly faster than relay 30. As the subscriber atstation I begins to dial relay 30 is energized and the circuit of relay3| is opened but, due to the slow releasing characteristics of relay 3!the relay is not allowed to release. However, after a period which beadjusted to be somewhat longer than the longest train of digit impulsesrelay 3| will relinquish its hold over relay 25. Since relay is veryslow to release, it will operate at the start of the first train ofincoming pulses and not release until a period after the ending of thelast train of such impulses as measured by its timing characteristic.Since relay 3| then will remain deenergized until the end of this latterperiod there will be ample time provided for the outpulsing.

Should the subscriber at station I pause too long between digits, whichmight give the brush 2| opportunity to catch up with or to overtakebrush N), then relay 3|) will release and by causing the energization ofrelay 3| will prevent the further stepping of brush 2| until it isassumed that the brush H] has advanced.

It will further be understood that the brushes l0 and 2| may have nonormal position and that there is no necessary limit to the number ofcondensers H or 22 that may be provided. The terminals to which thesecondensers are connected may be placed in a complete ring. While thisstep-by-step switch is shown as a single row of contacts traversed bytwo brushes, it will be understood that two simple and conventionalswitches may be used.

What is claimed is:

1. A pulse repeater comprising in combination a condenser, means forcharging said condenser in accordance with a series of impulses, adevice for controlling a pair of conductors, an interrupter forproducing pulses over said pair of conductors, means for connecting saidcondenser to said device whereby said device is operated from the chargeon said condenser, and means controlled by said interrupter forwithdrawing from said condenser a portion of the charge with each pulsewhereby said device releases after the production by said interrupter ofas many pulses over said pair of conductors as were in the series usedto charge said condenser.

2. A pulse repeater comprising an energy reservoir, means for recordingthe number of incoming pulses in a train by adding a predeterminedquantity of energy to said reservoir for each said pulse in a train,means responsive to the rise of energy in said reservoir above a givencritical level for controlling means for transmitting outgoing pulses,and means for subtracting a predetermined quantity of energy from saidreservoir for each pulse transmitted.

3. A pulse regenerator comprising a storage condenser, means forrecording the number of incoming pulses in a train by adding apredetermined charge to said condenser for each pulse in a train, meansresponsive to the rise of the charge in said condenser above a givencritical level for controlling means for transmitting outgoing pulses,and means for subtracting a predetermined charge from said condenser foreach pulse transmitted.

4. A pulse regenerator comprising a comparatively large capacity storagecondenser, means comprising a comparatively small capacity condenser forrecording the number of incoming pulses in a train by transferring acharge from said comparatively small capacity condenser to saidcomparatively large capacity condenser for each pulse in a train, meansresponsive to the rise of the charge in said comparatively largecapacity condenser above a given critical level for controlling meansfor transmitting outgoing pulses, and means comprising a comparativelysmall capacity condenser for subtracting a predetermined charge fromsaid comparatively large capacity condenser for each pulse transmitted.

5. A pulse regenerator comprising a compara tively large capacitystorage condenser, means comprising a comparatively small capacitycondenser for recording the number of incoming pulses in a train bytransferring a charge in one direction from said comparatively smallcapacity condenser to said comparatively large capacity condenser foreach pulse in a train, means responsive to the rise of the charge iiisaid comparatively large capacity condenser above a given critical levelfor controlling means for transmitting outgoing pulses, and means forsubtracting a predetermined charge from said comparatively largecapacity condenser for each pulse transmitted comprising a comparativelysmall capacity condenser for transferring a charge in the oppositedirection to said comparatively large capacity condenser.

6. A pulse regenerator comprising a storage condenser, a relayresponsive to incoming pulses, means comprising a condenser charged onthe release of said relay and connected in parallel with said storagecondenser on the operation of said relay for recording the number ofincoming pulses in a train, means responsive to the rise of the chargein said storage condenser above a given critical level, precision meansfor transmitting outgoing pulses of predetermined length, strength andspacing, means controlled by said condenser charge level responsivemeans for rendering said precision means operative, and means controlledby said precision means while operative comprising a condenseralternately charged and connected in parallel with said storagecondenser in cycles corresponding in number to the number of outgoingpulses.

7. A pulse regenerator comprising a storage condenser and two matchedcondensers one for adding charges to said storage condenser and one forsubtracting equal charges from said storage condenser, means forcontrolling said adding condenser by incoming impulses, means forcontrolling said subtracting condenser in accordance with outgoingimpulses, and means responsive to the rise of the charge in said storagecondenser above a given critical level for rendering said last meansoperative.

8. A pulse regenerator for repeating a plurality of trains of pulses,comprising a plurality of storage condensers each for recording thenumber of pulses in a train through the rise of the charge therein abovea given critical level, a relay responsive to incoming impulses, acondenser controlled by said relay to alternately charge and transferits charge to one of said storage condensers, a step-by-step switchunder control of said relay for advancing the association of saidcondenser with said storage condensers at the end of each train ofpulses, another step-by-step switch under control of said storagecondensers and responsive to the charged condition of said storagecondensers above said given critical level, machine controlled means fortransmitting outgoing impulses, and another condenser controlled by saidmachine controlled means to alternately charge and transfer its chargeto one of said storage condensers whereby the number of pulses in atrain of outgoing pulses is measured by the return of the charge of saidstorage condenser to said given critical level.

KARL D. SWARTZEL, JR.

